Studies on the effects of the beta-halo derivatives of D-alanine on D-amino acid transaminase will be continued. Kinetic studies on the alpha-protio and alpha-deuterio derivatives of these compounds are underway along with similar studies on the relative rates of reaction of the beta-fluoro and beta-chloro-D-alanines with the enzymes. Through such an approach we hope to ascertain the rate-limiting step in this beta-elimination reaction. Studies on the primary sequence of D-amino acid transaminase will be continued. We have already determined the first 30 amino acid residues of the dimeric enzyme. During the coming year we will attempt to isolate peptides obtained by cleavage of the protein by cyanogen bromide and by clostripain.